<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="./css/inputnumber.css" />
    <link rel="stylesheet" href="./css/index.css" />
    <title>购物车</title>
  </head>
  <body>
    <div class="app-container" id="app">
      <!-- 顶部banner -->
      <div class="banner-box"><img src="./img/fruit.jpg" alt="" /></div>
      <!-- 面包屑 -->
      <div class="breadcrumb">
        <span>🏠</span>
        /
        <span>购物车</span>
      </div>
      <!-- 购物车主体 -->
      <div class="main" v-if="fruitList.length > 0">
        <div class="table">
          <!-- 头部 -->
          <div class="thead">
            <div class="tr">
              <div class="th">选中</div>
              <div class="th th-pic">图片</div>
              <div class="th">单价</div>
              <div class="th num-th">个数</div>
              <div class="th">小计</div>
              <div class="th">操作</div>
            </div>
          </div>
          <!-- 身体 -->
          <div class="tbody">
            <div v-for="(item, index) in fruitList" :key="item.id" class="tr" :class="{active: item.isChecked}">
              <div class="td"><input type="checkbox" v-model="item.isChecked" /></div>
              <div class="td"><img :src="item.icon" alt="" /></div>
              <div class="td">{{item.price}}</div>
              <div class="td">
                <div class="my-input-number">
                  <button :disabled="item.num <= 1" class="decrease" @click="sub(item.id)"> - </button>
                  <span class="my-input__inner">{{item.num}}</span>
                  <button class="increase" @click="add(item.id)"> + </button>
                </div>
              </div>
              <div class="td">{{item.price * item.num}}</div>
              <div class="td"><button @click="del(item.id)">删除</button></div>
            </div>
          </div>
        </div>
        <!-- 底部 -->
        <div class="bottom">
          <!-- 全选 -->
          <label class="check-all">
            <input type="checkbox" v-model="isAll" />
            全选
          </label>
          <div class="right-box">
            <!-- 所有商品总价 -->
            <span class="price-box">总价&nbsp;&nbsp;:&nbsp;&nbsp;¥&nbsp;<span class="price">{{totalPrice}}</span></span>
            <!-- 结算按钮 -->
            <button class="pay">结算( {{totalCount}} )</button>
          </div>
        </div>
      </div>
      <!-- 空车 -->
      <div class="empty" v-else>🛒空空如也</div>
    </div>
    <script src="../vue.js"></script>
    <script>
      const defaultArr = [
      {
              id: 1,
              icon: './img/火龙果.png',
              isChecked: true,
              num: 2,
              price: 6,
            },
            {
              id: 2,
              icon: './img/荔枝.png',
              isChecked: false,
              num: 7,
              price: 20,
            },
            {
              id: 3,
              icon: './img/榴莲.png',
              isChecked: false,
              num: 3,
              price: 40,
            },
            {
              id: 4,
              icon: './img/鸭梨.png',
              isChecked: true,
              num: 10,
              price: 3,
            },
            {
              id: 5,
              icon: './img/樱桃.png',
              isChecked: false,
              num: 20,
              price: 34,
            },
      ]
      const app = new Vue({
        el: '#app',
        data: {
          // 水果列表
          fruitList: JSON.parse(localStorage.getItem('list')) || defaultArr
        },
        computed: {
          //默认计算属性：只能获取不能设置，要设置需要写完整写法
          /* isAll () {
            //必须所有的小选框都选中，全选按钮才选中 -> every
            return this.fruitList.every(item => item.isChecked === true)
          } */

          //完整写法 = get + set
          isAll: {
            get () {
              return this.fruitList.every(item => item.isChecked === true)
            },
            set (value) {
              //基于拿到的bool值，要让所有的小选框同步状态
              this.fruitList.forEach(item => item.isChecked = value)
            }
          },
          //统计选中的总数
          totalCount () {
            return this.fruitList.reduce((sum, item) => {
              if (item.isChecked) {
                //选中 -> 需要累加
                return sum + item.num
              }else {
                //没选中，不需要累加
                return sum
              }
            }, 0)
          },
          //统计选中的总价
          totalPrice () {
            return this.fruitList.reduce((sum, item) => {
              if (item.isChecked) {
                //选中 -> 需要累加
                return sum + (item.num * item.price)
              }else {
                //没选中，不需要累加
                return sum
              }
            }, 0)
          }
        },
        methods: {
          del (id) {
            this.fruitList = this.fruitList.filter(item => item.id !== id)
          },
          add (id) {
            //1. 根据id找到数组中的对应项 -> find
            const fruit = this.fruitList.find(item => item.id === id)
            //2. 操作num数量
            fruit.num++
          },
          sub (id) {
            //1. 根据id找到数组中的对应项 -> find
            const fruit = this.fruitList.find(item => item.id === id)
            //2. 操作num数量
            fruit.num--
          }
        },
        watch: {
          fruitList: {
            deep: true,
            handler (newValue) {
              //需要将变化后的newValue存入本地（转json）
              localStorage.setItem('list', JSON.stringify(newValue))
            }
          }
        }
      })
    </script>
  </body>
</html>
